This works best on a wider screen. The comparison and data tables are wide, so scroll them sideways to see every column. The gear number stays pinned on the left as you scroll.
70 rpm
175 W
235 lbs
Units
Current drivetrain
Numbers must be in ascending order
Proposed drivetrain
Numbers must be in ascending order
What you gain
What you lose
The verdict
| Gear | Sprocket | Speed | Sustained Grade | Jump % | ||||
|---|---|---|---|---|---|---|---|---|
| Current | Proposed | Current | Proposed | Current | Proposed | Current | Proposed | |
Speed across all gears: current vs proposed
Full data — gear ratio, gear inches, development, gain ratio
Current drivetrain
| Gear | Ring/Cog | Ratio | Gear Inches | Dev (m) | Gain Ratio |
|---|
Proposed drivetrain
| Gear | Ring/Cog | Ratio | Gear Inches | Dev (m) | Gain Ratio |
|---|
About the numbers. Speed uses nominal wheel diameter at your set cadence. Sustained grade is an estimate of the steepest gradient you could hold at your set cadence and power under steady conditions: a practical approximation, not a precise physical prediction. Gear inches = wheel diameter × ratio. Development = wheel circumference × ratio. Gain ratio = (wheel radius ÷ crank length) × ratio. Jump percentages measure cadence drop when shifting to the next easier gear: green ≤15% smooth, orange 16–22% noticeable, red >22% large. Grade is shown to one decimal place. Grades above 30% are shown as >30%, beyond the practical range of sustained seated climbing for most riders.
Why this exists
This started from the annoyance of opening two browser tabs and a spreadsheet just to compare one gear setup against another. It handles 1x, 2x, and 3x drivetrains, flags cross-chained combinations automatically, and shows the math behind every number instead of just a verdict. How the numbers are calculated